Queen's University's Doug Munoz has found that Alzheimer's and Parkinson's patients perform poorly on tests that measure their control over fast eye movements called saccades, in ways that are distinctive for each disease.

Fast eye movements (or saccades) are researched quite extensively as they seem to give an indication of brain function, and can be affected by genetic abnormalities, mental illness and certain drugs (as this review reported, and as Christian's own research has indicated).